US4082427A - High refractive index glass compositions - Google Patents

High refractive index glass compositions Download PDF

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US4082427A
US4082427A US05/771,358 US77135877A US4082427A US 4082427 A US4082427 A US 4082427A US 77135877 A US77135877 A US 77135877A US 4082427 A US4082427 A US 4082427A
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glass
beads
refractive index
particles
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US05/771,358
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Nobuyuki Nakashima
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Fukuoka Tokushugarasu KK
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Fukuoka Tokushugarasu KK
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C12/00—Powdered glass; Bead compositions
    • C03C12/02—Reflective beads
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/12—Silica-free oxide glass compositions
    • C03C3/127—Silica-free oxide glass compositions containing TiO2 as glass former
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/12—Reflex reflectors
    • G02B5/126—Reflex reflectors including curved refracting surface
    • G02B5/128—Reflex reflectors including curved refracting surface transparent spheres being embedded in matrix
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S501/00—Compositions: ceramic
    • Y10S501/90—Optical glass, e.g. silent on refractive index and/or ABBE number
    • Y10S501/901—Optical glass, e.g. silent on refractive index and/or ABBE number having R.I. at least 1.8
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
    • Y10T442/259—Coating or impregnation provides protection from radiation [e.g., U.V., visible light, I.R., micscheme-change-itemave, high energy particle, etc.] or heat retention thru radiation absorption
    • Y10T442/2598—Radiation reflective

Definitions

  • This invention concerns the compositions of high refractive index glass suited for making reflex-reflective glass beads of refractive indices over 2.15.
  • High refractive index glass beads are highly essential material in the manufacture of reflective sheeting used for traffic signs for night traffic safety, vehicle stickers, reflective cloth, reflective paint etc.
  • reflective sheeting of high brilliance is specially necessary, but in the manufacture of such reflective sheeting of high brilliance, glass beads with high refractive inices are essential.
  • this invention is for supplying superior quality high refractive index glass that is the source of the glass beads used in high brilliance reflective sheeting.
  • This invention concerns the compositions of high refractive index glass with refractive indices of over 2.15 for making glass beads of 0.03 to 0.1 m/m diameter that are suited for the manufacture of high brilliance reflective sheeting, with a special feature that PbO is not used in the composition.
  • the glass of our invention containing no PbO whatsoever, is a skillful mixture of high percentage by weight of TiO 2 -- with a specie of alkaline earth oxide -- that has a rather high rate of devitrification, and several kinds of oxides in appropriate amounts to prevent devitrification.
  • TiO 2 is used as the main constituent mixed with at least 2 kinds of alkaline earth oxides (BaO, CaO, MgO, SrO) and ZnO and at least one of (MoO 3 , ZrO 2 ) and at least one kind of alkaline metal oxides (Na 2 O, K 2 O, Li 2 O) as indispensable ingredients.
  • the range of the compositions of this invention is shown as follows in Table 1.
  • One of the special feature of the glass of this invention is the fact that by the co-existence of ZnO and a very small amount of alkali metal oxide mixed with MoO 3 and or ZrO 2 , the fusion of high TiO 2 content glass is facilitated and devitrification is prevented. Next is an explanation of each ingredient.
  • TiO 2 which has a melting point of about 1830° C and a refraction index of about 2.53 to 2.71 is the ingredient that contributes mostly to the high refractive index of our glass, but its high concentration increases the rate of devitrification, so for our invention it is preferred to keep the percentage by weight under 65%.
  • BaO which has a melting point of about 1923° C and a refraction index of about 1.98 contributes to the promotion of the fusibility of our glass, but since it is an ingredient that decreases the refraction index of the glass, 30% is the maximum for our glass.
  • CaO having a melting point of about 2570° C and an index of refraction of about 1.84, mixed in small amounts is effective in the prevention of devitrification of our glass, however, if the amount is too great, it accelerates the rate of devitrification instead, so 10% is the maximum for CaO in our glass.
  • MgO having a melting point of about 2800° C and an index of refraction of about 1.74, mixed in small quantities is sometimes effective in the prevention of devitrification, but for our glass 2% is the maximum.
  • ZnO which has a melting point of about 1975° C and a refraction index of about 2.02, promotes the fusibility of our glass and is effective in the prevention of devitrification, but if the amount is too great, it promotes devitrification, so 15% is considered the limit for ZnO in our glass.
  • Glass forming oxides (B 2 O 3 , SiO 2 , Al 2 O 3 , P 2 O 5 ) in small amounts is effective in some cases for prevention of devitrification of our glass, but 2% of glass-forming oxides is considered the limit.
  • Examples of composition according to this invention are shown in Table 2 with the refractive index (ND) of each resulting glass.
  • titanium oxide is used.
  • alkali earth oxides carbonates, nitrates and hydroxides are used.
  • ZnO zinc white is used.
  • MoO 3 molybdenum trioxide is used.
  • alkaline metal oxides carbonates and nitrates are used.
  • B 2 O 3 boric acid is used.
  • SiO 2 powdered silica is used.
  • Al 2 O 3 aluminum hydroxide is used.
  • P 2 O 5 calcium phosphate is used.
  • the batch (mixture of ingredients) is placed in an alumina or platinum crucible and turned into a molten state by heating at approximately 1400° C.
  • a greater TiO 2 content in the glass tends to require higher temperatures. Care must be exercised so that the reducing flame does not come into contact with the glass, as it would cause brownish coloring in the glass. Fusion is completed in less time than for ordinary soda glass and the fused glass has a low viscosity.
  • the small pieces of glass comminuted by sudden chilling are dried, pulverized and screened to the prescribed size of powdered glass to prepare beads of 0.03 - 0.1 mm. Then by methods well known to the art, the particles are heated while suspended in air at a temperature of 1300° C to 1500° C, and each powdered glass particle becomes a spheriod by surface tension in a short time. In order to prevent devitrification, the glass particle that has become spherical must be rapidly cooled. Also during the process of making the glass particles into spheriods, reducing flame must not come into contact with the glass particles, as it would cause a brownish coloring the glass. In this way, superior quality glass beads which are colorless and transparent, and with high index of refraction can be obtained.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Glass Compositions (AREA)

Abstract

Disclosed are glass compositions that are particularly suited for making colorless and transparent reflex-reflective glass beads with refractive indices over 2.15. These lead-free glass compositions are made with TiO2 as the main constituent mixed with alkaline earth oxides and alkaline metal oxides, etc.

Description

This is a continuation of application Ser. No. 591,650, filed June 30, 1975, now abandoned.
FIELD OF THE INVENTION
This invention concerns the compositions of high refractive index glass suited for making reflex-reflective glass beads of refractive indices over 2.15.
BACKGROUND OF THE INVENTION
High refractive index glass beads are highly essential material in the manufacture of reflective sheeting used for traffic signs for night traffic safety, vehicle stickers, reflective cloth, reflective paint etc. For road signs erected on high speed highways, reflective sheeting of high brilliance is specially necessary, but in the manufacture of such reflective sheeting of high brilliance, glass beads with high refractive inices are essential. In particular, this invention is for supplying superior quality high refractive index glass that is the source of the glass beads used in high brilliance reflective sheeting.
Since reflective sheeting having high reflective brilliance must maintain its high brilliance even in rainy weather, it is essential that the reflective sheeing have a flat surface. Glass beads are closely packed in a single layer facing the surface within the thin binder (sheet) of transparent synthetic resin (colored or colorless), but said synthetic resin decreases the effectiveness of the glass to act as a spherical lens. Therefore glass beads for high brilliance reflective sheeting requires specially high refractive index glass, for example, for synthetic resin having a refractive index of 1.5 glass with refractive index of about 2.17 and over, and for synthetic resin having a refractive index of 1.45 glass with refractive index of about 2.1 and over, are required.
This invention concerns the compositions of high refractive index glass with refractive indices of over 2.15 for making glass beads of 0.03 to 0.1 m/m diameter that are suited for the manufacture of high brilliance reflective sheeting, with a special feature that PbO is not used in the composition.
Compared to ordinary glass, as unusually high refractive index glass beads for high brilliance reflective sheeting are easily subject to a phenomena of devitrification during the productions stages, special consideration must be given during the production process and also use glass compositions that do not easily cause devitrification. The best means of preventing devitrification during the production process of the glass beads is to chill the beads as rapidly as possible, but there is a limit to that also.
In the past, a high PbO content glass was used for producing glass beads possessing refrative indices of about 2.15 and over that were used for high brilliance reflective sheeting, but from the health standpoint, the use of large amounts of PbO, not only during its manufacturing stages but also in the use of the products, is not desirable.
THE INVENTION
The glass of our invention, containing no PbO whatsoever, is a skillful mixture of high percentage by weight of TiO2 -- with a specie of alkaline earth oxide -- that has a rather high rate of devitrification, and several kinds of oxides in appropriate amounts to prevent devitrification. For the compositions, TiO2 is used as the main constituent mixed with at least 2 kinds of alkaline earth oxides (BaO, CaO, MgO, SrO) and ZnO and at least one of (MoO3, ZrO2) and at least one kind of alkaline metal oxides (Na2 O, K2 O, Li2 O) as indispensable ingredients. The range of the compositions of this invention is shown as follows in Table 1.
              TABLE 1.                                                    
______________________________________                                    
GLASS COMPOSITION PERCENTAGE BY WEIGHT                                    
______________________________________                                    
TiO.sub.2               55 to 65%                                         
BaO                     17 to 30%                                         
CaO                      1 to 10%                                         
MgO                     0 to 2%                                           
SrO                     0 to 6%                                           
(However BaO + CaO + MgO + SrO                                            
                         18 to 35%)                                       
ZnO                      3 to 15%                                         
MoO.sub.3 + ZrO.sub.2   0.2 to 5%                                         
Na.sub.2 O + K.sub.2 O + Li.sub.2 O                                       
                        0.1 to 0.5%                                       
B.sub.2 O.sub.3 + SiO.sub.2 + Al.sub.2 O.sub.3 + P.sub.2 O.sub.5          
                         0 to 2%                                          
______________________________________
One of the special feature of the glass of this invention is the fact that by the co-existence of ZnO and a very small amount of alkali metal oxide mixed with MoO3 and or ZrO2, the fusion of high TiO2 content glass is facilitated and devitrification is prevented. Next is an explanation of each ingredient.
DETAILED DESCRIPTION
TiO2 which has a melting point of about 1830° C and a refraction index of about 2.53 to 2.71 is the ingredient that contributes mostly to the high refractive index of our glass, but its high concentration increases the rate of devitrification, so for our invention it is preferred to keep the percentage by weight under 65%.
BaO which has a melting point of about 1923° C and a refraction index of about 1.98 contributes to the promotion of the fusibility of our glass, but since it is an ingredient that decreases the refraction index of the glass, 30% is the maximum for our glass.
CaO, having a melting point of about 2570° C and an index of refraction of about 1.84, mixed in small amounts is effective in the prevention of devitrification of our glass, however, if the amount is too great, it accelerates the rate of devitrification instead, so 10% is the maximum for CaO in our glass.
MgO, having a melting point of about 2800° C and an index of refraction of about 1.74, mixed in small quantities is sometimes effective in the prevention of devitrification, but for our glass 2% is the maximum.
SrO, which has a melting point of about 2430° C and an index of refraction of about 1.87, mixed in small amounts is sometimes effective in the prevention of devitrification, but for our glass 6% is the maximum.
ZnO, which has a melting point of about 1975° C and a refraction index of about 2.02, promotes the fusibility of our glass and is effective in the prevention of devitrification, but if the amount is too great, it promotes devitrification, so 15% is considered the limit for ZnO in our glass.
MoO3, which has a melting point of about 795° C and a refraction index of about 2.08, and ZrO2, which has a melting point of about 2700° C and a refraction index of about 2.17, as aforementioned, by the co-existence of ZnO plus a very small amounts of alkali metal oxides, and if their total mixture is within 5%, it is very effective in the prevention of devitrification of our glass. By mixing alkali metal oxides (Na2 O, K2 O, Li2 O) in very small amounts together with ZnO is effective as aforementioned, but 0.5% of alkali metal oxides is considered the limit. Mixture of glass forming oxides (B2 O3, SiO2, Al2 O3, P2 O5) in small amounts is effective in some cases for prevention of devitrification of our glass, but 2% of glass-forming oxides is considered the limit. Examples of composition according to this invention are shown in Table 2 with the refractive index (ND) of each resulting glass.
              TABLE 2                                                     
______________________________________                                    
       (Percentage by Weight)                                             
Example No.                                                               
         1      2      3    4    5    6    7    8                         
______________________________________                                    
TiO.sub.2                                                                 
         55.0   55.1   55.6 56.2 56.1 56.2 57.9 57.4                      
BaO      22.0   24.2   24.4 27.8 24.6 29.5 22.6 25.0                      
CaO       1.9    5.2    4.1  2.9  1.7  1.0  4.2  5.4                      
MgO       1.8                     1.0                                     
SrO                     1.8  3.5  5.9       4.0                           
ZnO      14.6   12.2   13.4  6.0  7.0  9.2 10.5  8.5                      
MoO.sub.3                                                                 
          2.6           0.2  3.5       3.8  0.4  1.5                      
ZrO.sub.2        3.0    0.1       2.4  0.2       1.7                      
Na.sub.2 O       0.1         0.1       0.1                                
K.sub.2 O                                                                 
          0.1           0.1       0.1       0.1                           
Li.sub.2 O       0.2                             0.3                      
B.sub.2 O.sub.3                   1.2       0.3                           
SiO.sub.2               0.3                                               
Al.sub.2 O.sub.3                                                          
           2.0                                   0.2                      
 nD       2.15   2.15   2.15                                              
                             2.16                                         
                                  2.15                                    
                                       2.17                               
                                            2.16                          
                                                 2.16                     
______________________________________                                    

______________________________________                                    
Example No.                                                               
         8      10     11   12   13   14   15   16                        
______________________________________                                    
TiO.sub.2                                                                 
         57.3   58.5   58.3 58.9 59.3 59.6 59.8 60.0                      
BaO      23.2   22.4   24.0 24.5 25.3 26.2 24.1 26.4                      
CaO       7.3    5.4    3.5  5.2  6.0  4.0  2.6  4.3                      
MgO                     0.5                 0.8                           
SrO                     5.0                                               
ZnO       7.0    8.8    3.2  7.2  5.3  7.7  5.7  6.5                      
MoO.sub.3                                                                 
          1.1    4.8    0.1  3.5  4.0  0.3  2.5  0.1                      
ZrO.sub.2                                                                 
          3.7           4.9  0.2       0.3  2.5  2.2                      
Na.sub.2 O       0.1    0.3       0.1  0.1  0.5                           
K.sub.2 O                                                                 
          0.2           0.2  0.5       0.1       0.1                      
Li.sub.2 O                                                                
          0.2                          0.1       0.1                      
B.sub.2 O.sub.3                             0.1  0.1                      
SiO.sub.2                              1.0       0.2                      
Al.sub.2 O.sub.3                       0.6  1.4                           
 nD      2.16   2.18   2.17 2.17 2.19 2.17 2.17 2.19                      
______________________________________                                    

______________________________________                                    
Example No.                                                               
         17     18     19   20   21   22   23   24                        
______________________________________                                    
TiO.sub.2                                                                 
         60.0   61.6   61.5 62.5 62.1 63.3 63.4 64.7                      
BaO      26.3   23.5   28.9 27.0 21.0 20.2 17.5 18.5                      
CaO       5.6    3.0    3.3  4.7  8.5  1.2  4.5 10.0                      
MgO       2.0                     0.2                                     
SrO                               0.8            1.0                      
ZnO       5.0    6.8    4.5  4.0  5.8 14.8 13.2  3.5                      
MoO.sub.3                                                                 
          0.7    4.5    0.5  0.2  0.8  0.1  1.0  0.2                      
ZrO.sub.2                                                                 
          0.2    0.1    1.0  1.5  0.7  0.2  0.3  0.1                      
Na.sub.2 O                                                                
          0.2                0.1       0.1       0.1                      
K.sub.2 O               0.3       0.1  0.1                                
Li.sub.2 O       0.5                        0.1                           
B.sub.2 O.sub.3                                                           
SiO.sub.2                                        1.9                      
Al.sub.2 O.sub.3                                                          
 nD       2.19   2.18   2.20                                              
                             2.21                                         
                                  2.21                                    
                                       2.20                               
                                            2.21                          
                                                 2.19                     
______________________________________                                    

______________________________________                                    
Example No.  25       26       27     28                                  
______________________________________                                    
TiO.sub.2    64.3     65.0     65.0   64.1                                
BaO          19.8     17.0     20.2   19.8                                
CaO          9.9      1.0      1.0    7.3                                 
MgO          0.8                                                          
SrO                   0.5                                                 
ZnO          3.0      11.4     8.8    5.5                                 
MoO.sub.3    0.1      5.0      2.0                                        
ZrO.sub.2    0.1               2.6    1.1                                 
Na.sub.2 O   0.1                                                          
K.sub.2 O                      0.4    0.2                                 
Li.sub.2 O            0.1                                                 
B.sub.2 O.sub.3                                                           
             1.9                                                          
SiO.sub.2                                                                 
Al.sub.2 O.sub.3                                                          
P.sub.2 O.sub.5                       2.0                                 
 nD          2.19     2.23     2.22   2.19                                
______________________________________
The following is an explanation of the sources for materials used in the manufacture of our glass. Each of the materials must be of high purity and must have very little iron content, as iron content causes a brownish coloring in the glass.
For the TiO2 ingredient, titanium oxide is used. For alkali earth oxides; carbonates, nitrates and hydroxides are used. For ZnO, zinc white is used. For MoO3, molybdenum trioxide is used. For alkaline metal oxides, carbonates and nitrates are used. For B2 O3, boric acid is used. For SiO2, powdered silica is used. For Al2 O3, aluminum hydroxide is used. For P2 O5, calcium phosphate is used.
In the manufacture of our glass, the batch (mixture of ingredients) is placed in an alumina or platinum crucible and turned into a molten state by heating at approximately 1400° C. A greater TiO2 content in the glass tends to require higher temperatures. Care must be exercised so that the reducing flame does not come into contact with the glass, as it would cause brownish coloring in the glass. Fusion is completed in less time than for ordinary soda glass and the fused glass has a low viscosity.
Pour the molten glass immediately into cold water and comminute by this sudden chilling. This operation not only makes the pulverization of the glass convenient, but also prevents devitrification, however care must be exercised to have the entire glass melt chilled as quickly as possible.
To make the glass beads, the small pieces of glass comminuted by sudden chilling are dried, pulverized and screened to the prescribed size of powdered glass to prepare beads of 0.03 - 0.1 mm. Then by methods well known to the art, the particles are heated while suspended in air at a temperature of 1300° C to 1500° C, and each powdered glass particle becomes a spheriod by surface tension in a short time. In order to prevent devitrification, the glass particle that has become spherical must be rapidly cooled. Also during the process of making the glass particles into spheriods, reducing flame must not come into contact with the glass particles, as it would cause a brownish coloring the glass. In this way, superior quality glass beads which are colorless and transparent, and with high index of refraction can be obtained.

Claims (3)

What is claimed is:
1. Lead-free colorless and transparent glass suitable for formation at 1300° - 1500° C of colorless, transparent glass, beads having a refractive index exceeding 2.15 for use in reflex-reflective articles, and whose composition by weight percentage is:
______________________________________                                    
         % Range           Combined Range                                 
______________________________________                                    
TiO.sub.2  55 - 65                                                        
BaO        17 - 30                                                        
CaO         1 - 10                                                        
MgO        0 - 2               18 - 35%                                   
SrO        0 - 6                                                          
ZnO         3 - 15                                                        
MoO.sub.3  0 - 5                                                          
ZrO.sub.2  0 - 5               0.2 - 5%                                   
Na.sub.2 O 0 - 0.5                                                        
K.sub.2 O  0 - 0.5                                                        
Li.sub.2 O 0 - 0.5             0.1 - 0.5%                                 
B.sub.2 O.sub.3                                                           
           0 - 2                                                          
SiO.sub.2  0 - 2                                                          
Al.sub.2 O.sub.3                                                          
           0 - 2               less than 2%                               
P.sub.2 O.sub.5                                                           
           0 - 2                                                          
______________________________________
2. The process for preparing lead-free spherical glass beads of refractive index exceeding 2.15 which comprises the steps of forming a melt of glass having the composition according to claim 1; quenching said melt in a cold liquid medium; comminuting said glass into particles in the size range of 0.03 to 0.1 mm; suspending said particles in an air stream; heating said suspended particles to 1300° - 1500° C until softened whereby the surface tension of the softened glass converts said particles to spheroidal beads; rapidly cooling and collecting said beads.
3. Reflective articles comprising a support coated with a matrix film comprising a transparent resin polymer, said matrix film including a layer of the glass beads of refractive index greater than 2.15 according to claim 2.
US05/771,358 1974-07-02 1977-02-23 High refractive index glass compositions Expired - Lifetime US4082427A (en)

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JA49-75658 1974-07-02
US59165075A 1975-06-30 1975-06-30

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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0170518A2 (en) * 1984-08-03 1986-02-05 Minnesota Mining And Manufacturing Company Directionally imaged retroreflective sheeting
US4595627A (en) * 1985-02-06 1986-06-17 Safety Trim Industries, Inc. Fluorescent textile material
US4634724A (en) * 1984-08-31 1987-01-06 The Goodyear Tire & Rubber Company Crack resistant coating for masonry structures
US5674616A (en) * 1995-02-06 1997-10-07 Conversion Technologies International, Inc. Glass beads having improved fracture toughness
US5716706A (en) * 1995-04-18 1998-02-10 Minnesota Mining And Manufacturing Company Acid-resistant glass
US6204971B1 (en) * 1999-05-14 2001-03-20 3M Innovative Properties Company Glass microspheres for use in films and projection screen displays and methods
US6511739B2 (en) 1997-04-18 2003-01-28 3M Innovative Properties Company Transparent beads and their production method
US6514892B1 (en) 1997-04-18 2003-02-04 3M Innovative Properties Company Transparent beads and their production method
US20040259713A1 (en) * 2003-06-11 2004-12-23 3M Innovative Properties Company Microspheres comprising titania and bismuth oxide
US20080280034A1 (en) * 2007-05-11 2008-11-13 3M Innovative Properties Company Pavement marking and reflective elements having microspheres comprising lanthanum oxide and aluminum oxide with zirconia, titania, or mixtures thereof
US20100003514A1 (en) * 2006-09-14 2010-01-07 Japan Aerospace Exploration Agency Titanium-Containing Oxide Glass and Method for Production Thereof
US20100216625A1 (en) * 2003-01-10 2010-08-26 Nippon Sheet Glass Company, Limited Glass for laser machining
US7947616B2 (en) 2005-11-14 2011-05-24 3M Innovative Properties Company Pavement marking, reflective elements, and methods of making microspheres
WO2012099634A1 (en) * 2011-01-19 2012-07-26 Raytheon Company Solid solution-based nanocomposite optical ceramic materials
US8591045B2 (en) 2009-08-21 2013-11-26 3M Innovative Properties Company Pavement markings, reflective elements, and methods of making microspheres
US9012823B2 (en) 2012-07-31 2015-04-21 Raytheon Company Vehicle having a nanocomposite optical ceramic dome
US20160138230A1 (en) * 2014-07-29 2016-05-19 Patent Applied Technology Reflective Markings
US10927516B2 (en) * 2014-07-29 2021-02-23 Patent Applied Technology Luminescent markings
EP3822323A1 (en) 2019-11-18 2021-05-19 Ink Invent IP B.V. Retroreflective aqueous pseudoplastic gel composition for industrial spraying
EP3872138A1 (en) 2020-02-25 2021-09-01 Ink Invent IP B.V. Method for providing an aqueous composition with retroreflective properties
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EP0170518A2 (en) * 1984-08-03 1986-02-05 Minnesota Mining And Manufacturing Company Directionally imaged retroreflective sheeting
EP0170518A3 (en) * 1984-08-03 1988-06-01 Minnesota Mining And Manufacturing Company Directionally imaged retroreflective sheeting
US4634724A (en) * 1984-08-31 1987-01-06 The Goodyear Tire & Rubber Company Crack resistant coating for masonry structures
US4595627A (en) * 1985-02-06 1986-06-17 Safety Trim Industries, Inc. Fluorescent textile material
US5674616A (en) * 1995-02-06 1997-10-07 Conversion Technologies International, Inc. Glass beads having improved fracture toughness
US5716706A (en) * 1995-04-18 1998-02-10 Minnesota Mining And Manufacturing Company Acid-resistant glass
US5853851A (en) * 1995-04-18 1998-12-29 Minnesota Mining And Manufacturing Company Pavement marking tape comprising acid-resistant microspheres
US6514892B1 (en) 1997-04-18 2003-02-04 3M Innovative Properties Company Transparent beads and their production method
US6511739B2 (en) 1997-04-18 2003-01-28 3M Innovative Properties Company Transparent beads and their production method
US20010015846A1 (en) * 1999-05-14 2001-08-23 3M Innovative Properties Company Glass microspheres for use in films and projection screen displays
USRE38245E1 (en) 1999-05-14 2003-09-09 3M Innovative Properties Company Glass microspheres for use in films and projection screen displays and methods
US6765720B2 (en) 1999-05-14 2004-07-20 3M Innovative Properties Company Glass microspheres for use in films and projection screen displays
US6204971B1 (en) * 1999-05-14 2001-03-20 3M Innovative Properties Company Glass microspheres for use in films and projection screen displays and methods
US20100216625A1 (en) * 2003-01-10 2010-08-26 Nippon Sheet Glass Company, Limited Glass for laser machining
US20050143248A1 (en) * 2003-06-11 2005-06-30 3M Innovative Properties Company Microspheres having a high index of refraction
US20060293161A1 (en) * 2003-06-11 2006-12-28 Frey Matthew H Microspheres comprising titania and bismuth oxide
US7524779B2 (en) * 2003-06-11 2009-04-28 3M Innovative Properties Company Microspheres having a high index of refraction
US20090123754A1 (en) * 2003-06-11 2009-05-14 3M Innovative Properties Company Microspheres having a high index of refraction
US7585799B2 (en) * 2003-06-11 2009-09-08 3M Innovative Properties Company Microspheres having a high index of refraction
US20040259713A1 (en) * 2003-06-11 2004-12-23 3M Innovative Properties Company Microspheres comprising titania and bismuth oxide
US7947616B2 (en) 2005-11-14 2011-05-24 3M Innovative Properties Company Pavement marking, reflective elements, and methods of making microspheres
US20100003514A1 (en) * 2006-09-14 2010-01-07 Japan Aerospace Exploration Agency Titanium-Containing Oxide Glass and Method for Production Thereof
US7960300B2 (en) * 2006-09-14 2011-06-14 Japan Aerospace Exploration Agency Titanium-containing oxide glass and method for production thereof
US20110167870A1 (en) * 2006-09-14 2011-07-14 Japan Aerospace Exploration Agency Titanium-containing oxide glass and method for production thereof
US8030232B2 (en) 2006-09-14 2011-10-04 Japan Aerospace Exploration Agency Titanium-containing oxide glass and method for production thereof
US20080280034A1 (en) * 2007-05-11 2008-11-13 3M Innovative Properties Company Pavement marking and reflective elements having microspheres comprising lanthanum oxide and aluminum oxide with zirconia, titania, or mixtures thereof
US8591045B2 (en) 2009-08-21 2013-11-26 3M Innovative Properties Company Pavement markings, reflective elements, and methods of making microspheres
US9395467B2 (en) 2010-06-23 2016-07-19 Raytheon Company Solid solution-based nanocomposite optical ceramic materials
WO2012099634A1 (en) * 2011-01-19 2012-07-26 Raytheon Company Solid solution-based nanocomposite optical ceramic materials
US9012823B2 (en) 2012-07-31 2015-04-21 Raytheon Company Vehicle having a nanocomposite optical ceramic dome
US20160138230A1 (en) * 2014-07-29 2016-05-19 Patent Applied Technology Reflective Markings
US10927516B2 (en) * 2014-07-29 2021-02-23 Patent Applied Technology Luminescent markings
EP3822323A1 (en) 2019-11-18 2021-05-19 Ink Invent IP B.V. Retroreflective aqueous pseudoplastic gel composition for industrial spraying
WO2021099270A1 (en) 2019-11-18 2021-05-27 Ink Invent IP B.V. Retroreflective aqueous pseudoplastic gel composition for industrial spraying
EP3872138A1 (en) 2020-02-25 2021-09-01 Ink Invent IP B.V. Method for providing an aqueous composition with retroreflective properties
WO2021170634A1 (en) 2020-02-25 2021-09-02 Ink Invent IP B.V. Method for providing an aqueous composition with retroreflective properties
WO2022243227A1 (en) 2021-05-18 2022-11-24 Ink Invent IP B.V. Method for providing an organic solvent-based composition with retroreflective properties
WO2022243230A1 (en) 2021-05-18 2022-11-24 Ink Invent IP B.V. Organic solvent-based retroreflective composition for industrial spraying
WO2022243231A1 (en) 2021-05-18 2022-11-24 Ink Invent IP B.V. Retroreflective composition for industrial 3d spraying of large surfaces
EP4261251A1 (en) 2022-04-13 2023-10-18 Ink Invent IP B.V. Vehicle with improved lidar-detectable coating
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